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Demon has a freakin’ TransBrake

by Patrick Rall on

This week’s 2018 Dodge Challenger SRT Demon teaser might be one of the most exciting thus far: the upcoming Mopar muscle car will be the first ever road-going car equipped with a TransBrake.

That’s right – the new Demon is going to come from the factory with a TransBrake built into the 8-speed automatic transmission, allowing it to get away from the line harder and more consistently than when launching strictly with the brakes.

What is a Transbrake?
When a driver launches the average automatic-transmission car at the drag strip, they pull into the staging beams, holding the brake pedal down with their left foot and easing into the throttle with their right foot to increase engine speed before the launch. This method has been used by most drag racers since the dawn of the automatic transmission, but it has its shortcomings.

The biggest issue is that as you add power to the rear wheels, you increase the chances of spinning the rear tires in place or of overpowering the front brakes, pushing the car through the staging beams with the front tires locked. This is especially true of high performance cars with skinny front tires, like the 2018 Challenger Demon, since those narrow front tires have such a small surface contact area on the ground.

Most racers get around this is by installing a transbrake, which essentially “traps” the engine power in the transmission so as they increase engine RPM, there is no power working to spin the rear wheels or push the front wheels with the brakes locked. When the transbrake is released, all of that power is instantly sent to the rear wheels and the car rockets out of the hole with far more force than launching with the ol’ two-foot method.

Demon TransBrake
The 2018 Dodge Challenger SRT Demon is the first car to come with a TransBrake from the factory, so when the driver pulls to the line, bringing the engine up to the desired launch RPM and keeping it there will be easier than it is with any other road car. With this system engaged, the Demon will launch at 2,350 rpm without touching the brakes, while increasing launch boost pressure by 105% and launch torque levels by 120%. This system provides Demon 40% more torque on launch than trying to launch the car with skinny front tires using only the brakes.

The Demon TransBrake works in conjunction with the Torque Reserve system which we detailed last week (some might prefer to call that a 2-step or anti-lag) as part of the Launch Control feature. When this system is activated, the driver holds down the left shift paddle on the steering wheel, engaging the TransBrake, locking the output shaft, and allowing the driver to increase engine RPM and boost while the car stays stationary – all without touching the brakes. When the driver is ready to launch, they let off of the shift paddle and all of the Demon’s power is sent to the rear wheels in roughly 150 milliseconds, which is quicker than the delivery in a car being launched with the two-foot method, for improved track times in every metric.

The problem with an old-school transbrake is that when it is released, a tremendous amount of power is suddenly applied to critical drivetrain components. The Demon TransBrake has a unique preloading feature which applies a moderate amount of power to the drivetrain, but not enough to risk spinning the tires or moving the car. That helps protect the driveshaft, the rear differential and the axle shafts, but and also allows the power delivery to happen so quickly.

To showcase this exclusive feature, the newest teaser video for the 2018 Demon is titled “Lock and Load.”

Finally, this week’s teaser image comes with more mystery math on the Demon’s license plate and this time, we get the equation of 8.3+317=534…and your guess is as good as ours when it comes to deciphering any of these numbers.



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